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Electricity Again

I'm consolidating three welders onto one cart; a DialArc 250 on bottom followed by a Syncrowave 180 SD topped with a MM 135.

I'm merely stacking one welder on top of the other, i.e., no separating shelves / platforms.

As I would never be welding with any of these units at the same time, it seems logically permissible to wire the Syncrowave to the DialArc's lugs in parallel fashion and thereby need to only run one cable to the wall panel.

The DialArc has a 120 volt circuit split out so the MM 135 could be plugged in there.

If I understand you correctly, the smallest machine will derive its power from the one under it. Just make sure that the outlet on the machine has sufficient capacity to power it. On a Syncrowave 200 for example, the 115 Volt receptacles are limited to 15 amps. That may not be enough if your machine that provides the power is similar.

It would be best to have a separate connection for each machine, at least that's how I would do it.

Comment

The 115 V outlet on the 180SD is not stock. It has been added by connecting to one side of the 220. I'm just assuming it has ample amperage capacity to run the MM 135.

The DialArc is protected by a stock 10 A rated breaker mounted on the panel. However I don't think it would have any effect on the 120 circuit. It is most likely connected in such a manner so as to enforce the duty cycle of the welder even though it exceeds 90% even at settings at maximum amperage output.

Comment

The 115 V outlet on the 180SD is not stock. It has been added by connecting to one side of the 220. I'm just assuming it has ample amperage capacity to run the MM 135.

The DialArc is protected by a stock 10 A rated breaker mounted on the panel. However I don't think it would have any effect on the 120 circuit. It is most likely connected in such a manner so as to enforce the duty cycle of the welder even though it exceeds 90% even at settings at maximum amperage output.

If I understand you correctly, you are using one side of the 220V (Actually 240V nowadays) to derive 120V to power the MM135. Although there would certainly be sufficient power for the MM135 in the event that you decide to do it that way, it's not safe even though it does provide power.

The reason is that power in a 120V circuit is required to be derived from one line and its accompanying neutral, not the safety ground. If you have no neutral on a 120V line, you are putting power into your safety ground, something that it prohibited in electrical codes.

The correct way to power your MM135 which is a 120V device would be to have a neutral and a safety ground. The ground can be wired in with a separate 120V cable and a proper-sized breaker or, it can be done with a step-down isolation transformer. The transformer has one leg tied to ground and that leg can be used ti the other leg to provide an isolated source for your MM125.

The question arises why there is no neutral in a 220V line setup for a 220V welder. It's not needed since proper voltage is derived across the two lines (L1 and L2). The ground is there for safety. If there is also a 110 circuit in a 220 V welder, you can be certain that the makers (Miller, Lincoln, e.g.) will have incorporated an isolation transformer so that you can use the machine safely. I use the 15 amp 120 V outlet on my Miller Syncrowave to power my Bernard cooler.

So, please don't use one side of the 220 V power for 120 volts. If you still aren't sure, or if you don't believe me, get the services of a competent electrician to help you out.

No, I'm not an electrician , but I have worked on electrical systems in aerospace for many years and I learned that you need to follow codes.